Description

Phenytoin is an anticonvulsant medication used to control tonic‑clonic (grand mal) and psychomotor (temporal lobe) seizures in epilepsy, and to prevent seizures during or after brain surgery.

Prescription

phenytoin capsules are prescription-only and must be used under medical supervision 

Therapeutic Category

• Anticonvulsant (antiepileptic)
• Sodium channel blocker

 Active Ingredients / Composition

• Phenytoin sodium, available in strengths of 25 mg, 50 mg, 100 mg, or 300 mg capsules.

 Vitamins & Minerals

• None—phenytoin capsules do not contain added vitamins or minerals.
  

Variant &  Consume Type

• Hard gelatin capsules in various strengths (25–300 mg), intended for oral ingestion with water.

 Directions / Usage

• Adults generally begin with around 100 mg three times daily, adjusting up to maintenance of 300–400 mg daily in divided doses, or once‑daily extended‑release options if suitable.

• Routine blood level monitoring is required to ensure therapeutic range and avoid toxicity.

 Common Side Effects

• Nausea, stomach pain, loss of appetite
• Poor coordination, drowsiness, double vision
• Excessive hair growth, gingival enlargement
• Teratogenic effects if used during pregnancy (fetal hydantoin syndrome).

Serious Risks

• Liver dysfunction, blood dyscrasias (e.g. agranulocytosis, aplastic anemia)
• Steven‑Johnson syndrome (SJS), toxic epidermal necrolysis (TEN)
• Bone density loss due to vitamin D metabolism interference
• Psychological effects, including depression or suicidal thoughts
• Abrupt withdrawal may lead to seizure recurrence.

 Package Type

• Typically blister packs or bottles of hard capsules, depending on manufacturer and region.

Storage Advice

• Store at room temperature, below 30 °C
  Protect from moisture and light
• Keep out of reach of children

Safety Advice

• Do not use if allergic to phenytoin or other hydantoins
• Monitor liver and renal function, full blood count, and phenytoin serum levels during therapy
• Inform healthcare professionals prior to surgery or lab tests

• Avoid alcohol, which may alter drug levels
• Women who are pregnant or planning pregnancy require specialist consultation.

Product Substitutes

Phenytoin is available under many brand names worldwide, including:

• Dilantin, Epanutin, Phenytek, or local generic equivalents

• In the UK, marketed as Phenytoin Sodium Flynn Hard Capsules, still produced by Pfizer’s plant in Germany .
  

Manufacturer / Marketer

• The Exeter branded version is typically distributed by Exeter Pharmaceuticals, with marketing license varying by country.

• In the UK, Flynn Pharma holds licence; production remains at a Pfizer facility in Germany 

 Country of Origin

• Germany